The present invention relates in general to surgical instruments and surgical techniques. More particularly, the present invention is directed to a linear actuator for a multifunctional surgical tool for delivery of grafts, drugs, devices, and for irrigation/aspiration of various parts of the body; as well as surgical manipulation and extraction.
There is a need for a device to deliver, extract, and implant medical devices, drugs, tissue, etc. to various parts of the body. Such a device must be capable of delivering an implant in a target site in the body in a controlled, calibrated fashion where necessary. There is a need for implantation of neural and other living tissue, an increasing number of surgical devices, and drugs. In addition, existing implants frequently require treatment involving manipulation and extraction procedures. By way of non-limiting example, a significant number of patients receive vascular prosthetics, e.g. stents, which are provided by way of a catheter. It is desirable that vascular prosthetics and grafts be expressed from the catheter in a controlled and calibrated fashion. Further, there is a need to alter the position of such prosthetic devices in the body or to extract these devices. Likewise, there is a need to deliver, manipulate, and extract other medical and therapeutic devices.
Many self powered surgical tools have been developed which are capable of performing the previously mentioned tasks. Most of these tools have pneumatic drive means. U.S. Pat. No. 5,019,035 issued to Missirlian et al. discloses one such device. Missirlian describes a pneumatically operated microsurgical cutting instrument. A spring biased inner cutting member moves in a first direction relative to a stationary cutting member in response to the applied air pressure. A spring returns the inner cutting member to its original position. This system, like all pneumatic systems suffers from an inherent hysteresis in the system. This hysteresis limits the control that the operator has over the implement thereby complicating delicate procedures. Also, pneumatic systems tend to impart a "jerky" movement to the implement further affecting the precision and accuracy with which the tool can be effectively used. Finally, the pneumatic systems can be subject to leaky and clogged supply/vacuum lines which can affect performance.
U.S. Pat. No. 4,837,857 issued to Scheller et al. discloses a foot pedal assembly which can be used for remotely controlling a variety of microsurgical instruments. The system employs pneumatic drive means and is thereby subject to the aforementioned drawbacks.